Gentlemen:

I am blessed with a modest chunk of real estate that's on the back end of a cul-de-sac so it's pie shaped and has a long-ish run of fence aligned exactly on a north-south axis. A few years back I put in a pair of 30' telescopic TV masts 120' apart and hung a 136' off center fed dipole across them. Yeah, the ends drooped a bit and I had 5' of PVC on top of the metal for a bit of separation so the whole mess was 32' or so above the ground.

Worked well. Q'd the world during Cycle 23 with 100 watts. Two years ago a large-ish neighbor's tree split during a storm and took out the south mast. Now that Cycle 24 is on the way I'm thinking of how to re-do The Wonder Wire.

Thot: Visualize 280' of 10ga stranded copper arranged as a rectangle approximately 110' horizontally and 20' high, top wire is maybe 28' off the ground, bottom wire is around 8' up. The vertical rectangle is aligned true north-south along the plane of the wire. At the center of the bottom wire is an insulator and 800 ohm non-inductive resistor. At the center of the top wire there will be an insulator and home-brew open wire line  that runs maybe 60' to the house. At that point under an eave there is a dual core 4:1 Guanella current balun transitioning from the open wire line to a siamese pair of RG-62 (92 ohm) coaxial cables arranged as a shielded pair running through the attic to the radio room. The shields are tied together and grounded at both ends.

At the transceiver end of this mess will be another 4:1 dual core current balun making the transition from the two coax center wires to a PL-259. The concept here is ~800 ohms to ~184 ohms to ~50 ohms across two baluns, the goal is semi-decent all band HF coverage of 160 through 10 Meters.

Yes, I know the antenna is too low for serious DX on 160 and 75, might be a player on 40, could start to shine on 20 and up. Putting the feed line on the top wire does two things: Elevates the line well above the pedestrian hazard level and should put the most RF current at the greatest height. Patterns will range anywhere from pregnant blob to fat figure eight to June bug on a windshield depending on the band.

Question: Assuming the large-ish terminated loop is fairly non-resonant and mostly flat impedance wise, and the baluns aren't being asked to perform a miracle, will my feed losses be reasonably low?

Essentially what I'll have is a stretched terminated folded dipole 110' long with 20' of separation between the horizontal wires. Is an 800 ohm terminator a good starting point? The ratios work well with that number. Since the terminator on the bottom wire it's within stepladder height for tweaking, but I'd just as soon hit it about right the first time...

W8JJI wrote:
"Envision a pair of 20 or 17 meter 4 element monoband yagis mounted side by side, vertically on a horizontal boom of about 35 feet end to end."
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Got the picture, and know that anything can be done if you throw enough time and money at it, but OMG what a modest wind gust could do in terms of rotational torque on the tower and rotor... I'm visualizing a pair of 17' breaker bars with unequal wind catchers mounted on the ends. ( ! )

In the land of the tornado some of us think that way...

I can think of another possibility... Is there a balun anywhere between the radio and the HO loop? It has been a while since I've spent some quality time with Jerry Sevick's book on the subject, but do recall that a typical HF balun challenged by a hairy mismatch or pushed beyond its nominal frequency range can add distortion(s) to the radiated signal.

Is the HO loop we're talking about also used on HF? With the broadband nature of a big HF loop (very big @ 50 MHz?) and a balun that's misbehaving the spurs have a chance of doing some business around the neighborhood and beyond.

Anyone else been there, done that?

An aluminum paste would likely be the better choice as it avoids the possibility of electrolysis from dissimilar metals when wet. I used to use NoAlOx on every connection within an antenna until I discovered that it tends to migrate where I don't want it... Like into a gamma match or SO-239 connector block. Does a good job of attracting dirt if it gets on an insulator, too.

Chances are I'll be doing some antenna refurbing this spring and will likely use a graphite or molybdenum grease... Sparingly.

I'm having some problems getting the .PDF's to load, like maybe the web site is a bit gassy tonight, but poke around here

http://www.cpii.com/library.cfm/9

to see if you can pull up the conditioning, care and feeding, extending tube life topics.

Looked at some other links and they tell me that in the case of glass tubes the factory does a filament stress test (overvolt) and tube aging procedure before the part is shipped. Ceramic tubes should get a factory burn and spec check, especially on the high-dollar items... If it were me I wouldn't want to see them come back with a nastygram from the customer.

And W8JJI brings up a good point indirectly... In the case of long-ish SSB work on 2 Meters anything over 60 miles or so is probably over the horizon for the typical Q.

If you're relying on reflection or refraction to make the path, can you rely on the polarization remaining intact? Or that the beam heading that worked so very well last night is going to work tonight?

Disclaimer: I have no 2 Meter SSB rig and the closest direct experience I have is on 6 Meter SSB where propagation is whatever it wants to be. Not where, when or what I want it to be... Every CQ is a fresh roll of the dice.

Virtually all new construction on FM broadcast antennas use circular polarization and have been moving that way for 20 years or better. Used to be all horizontal. While 2 Meter amateur doesn't have the same diversity of receiver situations as broadcast does, a circular polarization is useful in reducing multipath issues and selective fading in both applications.

I haven't looked at mfr's specs for a while, but recall that some crossed beams could be rigged for circular polarization. Could be useful as a universal SSB / FM setup, might also prove useful for Sporadic-E openings.

(?)

This might be a VHF question... The M2 "Horizontal Omni Loop" looks like this in the 2 Meter flavor:

http://www.m2inc.com/products/vhf/2m/2mholoop.html

Plus, there is a 6 Meter option which can be stacked with  its smaller sibling:

http://www.m2inc.com/products/6m/6mloop.html

Disclaimer: I am in no way associated with M2, the letter M does not appear in my first, middle, or last names, and I've never been been accused of being squared. Not even by crazy people...

Look for a CR-2025 coin sized 3v lithium battery on the control board located behind the front panel. Could be marked as 'BAT4001' on the board.

That's a 30 second task for a search engine...

http://www.radioamateur.eu/schemi/FT2700_serv.pdf

I have no experience with the tuner... But... I think this has come up before. Looking at the user's manual:

www.mfjenterprises.com/man/pdf/MFJ-993B.pdf

The block diagram on page 30 shows an external jumper has to be installed across the two binding posts with the * between them to connect Antenna 1 to the internal balun.

I think you should hear equal RX band noise from either terminal of the balanced line binding posts through the balun if it's jumpered correctly. If you can hear noise only by touching the jumper across the * and nothing from either 'balanced line' post the balun is probably open...

I'm assuming you're touching only one of the posts at a time and not touching the radio case or tuner ground.

(?)

Yeah, and the queers will be getting married every Saturday night on 3950...!

I won't know what to make of any of this until Rehab Rush tells me what to think.

Speaking from the perspective of a Standard Broadcast DX'er who has screwed around with a variety of low band RX antenna types... If you want to watch your S-Meter dance into the big numbers, go with a longwire through a 9:1 single core voltage balun and a decent ground on the coax shield. Absolutely the best in terms of signal strength, but, they do tend to be noisy.

Next best in terms of raw signal strength is a resonant loop. 6-7 turns of wire on the largest frame you can tolerate indoors. Wire a large-ish variable cap across the loop, wind a single turn loop within the frame and hook the single turn loop to your RX. Adjust the cap and rotate the loop for best signal. Sigs will be less than the longwire, but the noise will also be much less. Between the two the loop will be a much more 'listenable' antenna even if your inner anal-retentive insists you tweak it every time you QSY.

These two antennas are definitely best on the low bands but not so good above 4 MHz or so.

Slightly less in terms of signal strength but the best overall compromise is an outdoor terminated loop. Run a loop of #14 copper outdoors using whatever supports are convenient. Try to get the largest enclosed area inside the loop for the space you have to work with. Use a 4:1 current balun at the feed point and install a 400 - 600 ohm 1 or 2 watt non-inductive resistor approximately midway between the loop ends. You'll have reasonably good RX from the AM BCB through 10 Meters and a quiet noise floor.

The noise floor thing is important as I'm using a terminated loop this winter and it's amazing how much a signal can fade but remain listenable compared to the typical dipole or longwire. A resonant loop has the same properties, but as an SWL antenna it's lame by comparison.

You might consider a seven-ish turn loop with a resistor in the middle and 4:1 balun to your RX if an outdoor loop isn't a good option for you... Hang it on an exterior wall and see what happens.

On a related note: I've had a recurring problem with the battery terminals on the car I use daily. About every six months they needed to be removed, cleaned up with a ScotchBrite pad, re-greased and re-installed.

Fixed the problem every time.

Always used white Lithium grease as it's fairly clean (as far as greases go) and seems to do a good job of making the connection water and oxidation resistant. About two months ago I was de-junking the garage shelves and found two cans of WW II / Korean (?) surplus graphite grease I had bought years ago and forgot about. Some of you may recall them, packed in a brass colored shoe polish style can. The grease had dried out somewhat but a few drops of oil brought it back to a good working consistency.

It smells like.................. Victory.

Time will tell. I'm thinking a slightly conductive grease like a graphite or molybdenum might be the better choice for a compression fit application like battery terminals and ground rod clamps. And it doesn't 'run' like NoAlOx does.

Many radios of that vintage (and newer) use a series of relays to switch bandpass filters between the PA and SO-239. If one or more relays go bad it can affect transmit on some bands without affecting the receiver.

That would be the second thing I'd look at... First thing would be to confirm all switch and configuration settings, including the things you rarely use.